Some things you really ought to check out:

Kiva: A website dedicated to microfinancial lending to people in third world countries, charity thats free!
More here.

Games:

Dwarf Fortress: A rouge-like fortress building game of incredible complexity, where you slowly mine a fortress out of bare rock using your ever growing company of spirited (or sometimes not so spirited) dwarfs. If you are going to try it, use the tutorial here on the dedicated DF wiki.

Mount & Blade: A first or third person action adventure rpg, where you take your adventurer free roamingly around the world of caldera, joining factions, looting, or doing quests. The combat really makes this game great! (check the forums for the latest version)

Accursed Lands: A post apocalyptic MUD. Really lively vivid world, with many, many, things to do. Check here for more info.